According to the provisions of the Registration Act, which document is subject to registration only if it is presented to the proper officer within four months of its execution?

As per Section 23 of the Registration Act, 1908, no document, except a will, shall be accepted for registration unless it is presented for registration within four months from the date of its execution. This means only wills are exempted from this time limitation for registration. Other documents related to immovable property or otherwise (except wills) must be presented within this prescribed four-month period. Therefore, documents other than a will are subject to registration only if presented within four months, making option (a) the most accurate.